Mineral fiber production method and apparatus

ABSTRACT

Disclosed is a conventional apparatus for directing molten, mineral slag onto a spinner rotating on a horizontal axis with annularly arranged steam jets directed parallel to the rotational axis stripping the slag from the spinner and fiberizing it. This conventional fiber forming system is utilized with a collecting tube having a conical entry portion which is concentric with and faces the stream of fiberized material projected by the steam jets. The spacing of the mouth of the entry portion from the point of entry of the slag into the steam jets is such as to minimize entry of shot or unfiberized slag into the collecting tube. The fiberized material is further refined or stripped of unwanted particles by passing it through an inclined portion of the collecting tube and, sequentially, through two, cyclone-type centrifugal separators before collecting it in a conventional bagging apparatus.



1. A METHOD OF PRODUCING A HOMOGENEOUS MINERAL FIBER PRODUCT FROM A STREAM OF MOLTEN SLAG COMPRISING: RECTILINEARLY PROJECTING AND FIBERIZING THE SLAG BY ENTRAINING IT IN AN ANNULARLY ARRANGED ARRAY OF STEAM JETS; PROVIDING A COLLECTING TUBE CONCENTRIC WITH THE ANNULAR ARRAY OF STEAM JETS FOR RECEIVING THE FIBERIZED MATERIAL WITH THE OPEN RECEIVING END OF THE TUBE SPACED FROM THE POINT OF ENTRY OF THE SLAG INTO THE STEAM FLOW AND HAVING A DIAMETER SOMEWHAT LESS THAN THE OF THE REMAINDER OF THE TUBE TO PROVIDE A CONICAL ENTRY SECTION; CONNECTING THE END OF SAID COLLECTING TUBE REMOTE FROM THE ENTRY SECTION TO AN INITIAL CYCLONE-TYPE CENTRIFUGAL SEPARATOR; DROPPING THE DISCHARGE FROM THE LOWER END OF THE CYCLONE SEPARATOR THROUGH AN UNLOADING VALVE; DRAWING OFF THE FIBERIZED MATERIAL OF LESSER MASS THROUGH A HORIZONTAL TUBE COMMUNICATING WITH THE DISCHARGE FROM THE UNLOADING VALVE; PROVIDING A CONVEYING TUBE COMMUNICATING WITH THE HORIZONTAL TUBE AND WITH THE INTAKE OF A SECOND CYCLONE-TYPE CENTRIFUGAL SEPARATOR; PROVIDING AIR MOVING FANS FOR ESTABLISHING SUCTION IN SAID COLLECTING TUBE, HORIZONTAL TUBE, CONVEYING TUBE AND SAID CENTRIFUGAL SEPARATORS; AND PROVIDING A MEANS FOR ACCUMULATING THE HOMOGENEOUS PRODUCT ISSUING FROM THE LOWER END OF THE SECOND CENTRIFUGAL SEPARATOR.
 2. A method as claimed in claim 1 in which the unloading valve utilized takes the form of a rotary valve.
 3. A method as claimed in claim 1 in which both said collecting tube and conveying tube are inclined approximately 40* from the horizontal and connected to their respective separators at their high ends.
 4. An apparatus for producing a homogeneous mineral fiber product from a stream of molten slag comprising: means for fiberizing the slag by entraining the slag stream in an annularly configurated horizontal steam jet, a collecting tube having its open end spaced from the point of entry of the slag into the steam jet and concentrically aligned therewith for receiving the fiberized material, said receiving end of the collecting tube having a diameter somewhat less than that of the remainder thereof to provide a horizontal conical entry section, an initial cyclone-type centrifugal separator having its intake connected to the end of said collecting tube remote from said entry section, means for reducing the pressure in said collecting tube and separator to sub-atmospheric, an unloading valve receiving the discharge of the separator, a conveying tube having a horizontal portion communicating with the vertically falling discharge from said unloading valve, a second cyclone-type centrifugal separator having its intake communicating with said conveying tube, means for reducing the pressure in said conveying tube and said second separator below atmospheric, and means for accumulating the material discharged from said second separator.
 5. Apparatus as claimed in claim 4 in which both said collecting tube and conveying tube, beyond their entry section and horizontal portion respectively, are inclined approximately 40* from the horizontal and connected to their respective separators at their high ends.
 6. Apparatus as claimed in claim 1 in which the space between said open end of the collecting tube and said point of entry of the slag into the steam jet is in the range of 100 to 120 percent of the diameter of said open end of the collecting tube.
 7. Apparatus as claimed in claim 1 in which the space between said open end of the collecting tube and said point of entry of the slag into the steam jet is approximately 24 inches and the diameter of said open end of the collecting tube is approximately 22 inches. 